Fiber-optics links are known to possess the qualities of high bandwidth, low attenuation, and good electromagnetic interference (EMI) immunity. Because of these qualities, signals can be modulated at high frequencies, such as microwave frequencies, and transmitted over fiber-optic links. Optical transmitters and optical receivers, modulate and demodulate, respectively, the optical signals. Conventional optical modulators and demodulators are known to be nonlinear over wide bandwidths due to the nonlinearity attributed to propagation delays. Thus, the very qualities that make fiber-optic links attractive are negated by the nonlinear characteristics of optical modulators and demodulators. That is, a phase modulated (PM) fiber optic link employing a photonic phase locked loop phase demodulator has intrinsic linear response. The photonic phase locked loop performs phase demodulation by tracking the optical phase of a phase modulated optical signal. Photonic phased locked loops thus demand small loop latency.